This invention relates to a protecting plants from injury due to frost or freezing and, more particularly, to a composition, method, and apparatus for protecting plants from injury caused by frost or freezing temperatures.
When plants are exposed to freezing conditions during the growing season, temporary or permanent injury to the plants is likely to occur. Such injury is one of the leading causes of loss in the agricultural industry. It has been estimated that from 5 to 15 percent of the gross world agricultural product is lost to frost damage in one year. According to one estimate, approximately 10 billion dollars of agricultural products are lost annually to plant and crop freezing world-wide each year.
Frost sensitive plants and fruits generally cannot tolerate ice formation within their tissues and break down and become flacid and discolored as the plant begins to warm. Typically, during a light freeze when temperatures range between −2 C to 0 C (29 F/32 F), tender plants are often killed or damage with little effect on other vegetation. During a moderate freeze when temperatures range between −8 C and −2 C (25 F to 28 F), heavy damage will occur to most plants, including fruit blossoms and tender semi-hardy plants. During a severe freeze when temperatures drop below −9 C (24 F), heavy damage will occur to most plants.
Present methods of protecting vegetation from frost include warming the air surrounding the plants using heating devices, such as smudge pots, heat blowers and canopy heaters, placed near the plants; stirring the air over the plants by use of helicopters or air blowing equipment; and covering the plants with a insulating material such as water, fogs, material tarps, and foam sheeting material. Such methods of frost protection, however, are undesirable due to their tendency to pollute as in the case of heating devices, or are relatively expensive, as in the case of utilizing wind blowing devices or helicopters, or are relatively labor intensive as in the case of utilizing tarps or foam sheeting materials. Further, such frost protection devices often achieve limited success, particularly when the ambient air temperature falls well below freezing for a substantial amount of time or during windy conditions.
In addition to such physical methods, various chemical methods have been developed and used for reducing or preventing injury to vegetation caused by frost or freezing temperatures. Such methods include applying various chemical compounds onto the plants to be protected to lower the temperature at which plant damage occurs. Such chemical methods, however, tend to be unreliable, relatively expensive, and ecologically specious.
Accordingly, a need exists for a composition, method, and apparatus of protecting plants from injury caused by frost or freezing temperatures which is relatively inexpensive, environmentally acceptable, non-toxic, ecologically sound, and is not labor intensive.